The new process — needle ablation using in-catheter, heated, saline-enhanced, radio frequency (SERF) energy — creates lesion scars inside the heart muscle where life-threatening arrhythmias cause VT, Mayo Clinic said. Injecting heated saline at the same time as the RF energy is applied increases heat transfer compared to conventional methods of ablation, which means the ablation can treat tissue deeper in the heart wall than the surface.
Caused by irregular electrical signals in the lower chambers of the heart, VT can trigger heartbeats so rapid that the heart’s chambers don’t fill with blood properly. VT can also stop the heart entirely. Implantable cardioverter-defibrillators (ICDs) are used in many VT patients to correct the heart’s rhythm but can’t prevent arrhythmia.
The catheter was developed by Thermedical co-founder and CEO Michael Curley, with funding from the National Institutes of Health (NIH).
The trial used the catheter in needle electrode ablation on 32 participants, each with multiple episodes of VT that did not respond to drug therapy after an ICD implantation and standard ablation. The patients had about 45 shocks from their defibrillator in the six months before their procedure, Mayo Clinic said.
Needle electrode ablation immediately eliminated clinical ventricular tachycardia in 31 of the 32 patients, Mayo Clinic said, while device therapies such as shock or pace regulation dropped by 89% in the five months after the procedure.
Five patients in this high-risk group had complications, primarily in the earlier procedures, Mayo Clinic said.
Dr. Douglas Packer, a Mayo Clinic cardiac electrophysiologist, is the first author and principal investigator of the study. He’s also an unpaid consultant for Thermedical, which has funded his research along with NIH and its National Heart, Lung, and Blood Institute.
“This preliminary trial is important because it suggests that there is a new way to treat problematic ventricular tachycardia by reducing or eliminating the shocks that ICDs deliver,” Packer said in a news release. “It appears to be effective in achieving this goal. For clinicians, it provides hope that treatment in the electrophysiology lab may be effective, even if other treatments failed. For patients, it provides hope that their quality of life can be improved.”
The FDA granted Breakthrough Device Designation for Boston-based Thermedical’s SERF ablation system and Durablate catheter in 2020. That same year, the FDA and Health Canada approved Thermedical’s degassed saline for the first Durablate procedures. SERF ablation generates air bubbles that may contribute to procedure-related strokes, but the Durablate catheter and degassed saline decrease air bubbles by more than 98%.
Next up is a larger clinical trial to prove the findings and demonstrate the safety of the new SERF technology, Packer said.